All that said, I'm still not convinced optimised billboards are the best use of our time when we've got no batching whatsoever.

Other than the nuclear option of replacing OSG with hand-written rendering I don't have any ideas for that so I'm exploring something what could be done. Billboards aren't a silver bullet but nothing is, and at least this could allow replacer artists to do the work of tuning some distant features to look right instead of hoping for an algorithm to do it reliably. But even so, it's still not a solution for the vanilla game so pushing it beyond 1.0 is pretty much a given, if it ever even is supported.

Never attribute to bad code, that which can be adequately explained with clever hacks

We've got a pretty good design for a system that should 'just work'. It doesn't require abandoning OSG or even using it in ways it wasn't designed to be used. It's just that no one's implemented it yet.

Hey, I'm just intruding to add that I'm willing to help. I'm a rendering engineer by day (working on open world games) and I have some free time in the next couple of weeks. I don't know anything about OSG though

Am I correct that the current plan is to implement what's described in the paste bin link? (batching objects of a cell into one mesh + maybe cache + I guess building a texture atlas)

Now that shadows are being implemented, distant statics seems to be the last major feature remaining for inclusion in OpenMW. Have plop and/or others been able to make concrete progress on this recently? Thanks to all contributors for your work!